Animal Models of Systemic Mycoses

Blastomyces dermatitidis, a thermally dimorphic fungus, is a pulmonary pathogen in humans, ¹⁴ dogs, ^5,6 mice, ^7,8 and other mammals. ⁷ Untreated disseminated-human blastomycosis has been reported to have a mortality rate greater than 80%. ⁹ However, virulent and avirulent isolates of B. dermatitidis have been described ^8,10,11 and in five outbreaks, blastomycosis in some patients (28 of 46) resolved without therapy. ⁴ Blastomycosis is naturally acquired by way of the pulmonary route ¹² by inhalation of the infectious agent in its saprophytic or mycelial-conidia phase. Five documented point outbreaks, summarized by Sarosi et al. ³ and Tenenbaum et al., ⁴ have been associated with construction activity and postulated disturbance of B. dermatitidis in its ephemeral ecological niche. ^13-16 Although the dog was the first animal used in the study of blastomycosis ¹⁷ and in later epidemiological studies, ^5,6 the laboratory mouse has been 81the animal of choice for isolation of B. dermatitidis from nature ^13,14 and development of an animal model of pulmonary blastomycosis. ⁸ The murine model of pulmonary blastomycosis has been used extensively over the past several years for immunological ^18,21 and drug treatment studies, ^22,23 consequently it will be described first and in detail.